President Trump has rolled back several of former President Obama’s signature efforts to curb climate change.

An executive order, which Trump signed on March 28, starts the process to disassemble the Obama Clean Power Plan. A Trump administration official says that process likely will take a year and face legal challenges.

清洁电源计划为发电厂设定了碳排放限制，但美国最高法院持续下去，以等待法律挑战。

Further, the order reverses Obama administration guidance on how agencies should address climate change in National Environmental Policy Act reviews. It removes the requirement to include the social cost of carbon estimates in cost-and-benefit analyses for regulations.

In addition, it lifts a moratorium on leasing coal on federal lands and undoes Obama’s climate action plan and climate-change executive orders on adaptation and national security. The official says the Trump administration believes all those Obama actions exceeded federal legal requirements and hindered economic growth.